I knew X means Extreme and I already compared them before from the same link. What I realy wanted to ask is if I am not interested with OC and don't care about the frequency difference between QX9300 and Q9100 is there any other important difference which is not mentioned in the compare page? Which choise would be wiser, QX9300 or Q9100? Cause the prices quite different.

No I definetly will buy Q9100 but some other things are confusing me? In the market espacially China, there is a lot of Q9200 QAVR or QAJF. I checked intel's web page there is no such CPU. What is the reality about that CPU?